It is known to use dispensing caps and closures with beverage containers such as bottled water and sport beverages. A dispensing cap incorporates a reservoir for receiving a quantity or dose of an additive substance, to be mixed with the base liquid (e.g., water; sport beverage) in the container. The additive substance could be of various types, and could be in either liquid or powdered form; examples would include flavoring ingredients, medicinal or pharmaceutical agents, dietary supplements, and therapeutic substances. Some additives may have diminished efficacy if mixed with the base liquid a significant length of time before consumption, or early mixing could reduce the mixture's shelf life. In other cases, such as for medicinal, therapeutic, or other health-related additives, proper proportioning of the additive may be important to ensure that the additive will have the desired benefits for the person consuming the mixture. Provision of the additive in a dispensing cap facilitates precise proportioning of the additive and base liquid, and also allows a consumer to ensure optimal freshness of the additive/base liquid mixture by dispensing the additive into the base liquid just prior to consumption.
The prior art discloses numerous examples of container closures for dispensing an additive into the container, including the following patent documents:                DE 31 40 398 A1        DE 42 38 819 A1        FR 1178 115 A1        FR 2 814 156 A1        JP 2002-282565        U.S. Pat. No. 4,315,570 A1        U.S. Pat. No. 5,217,433        U.S. Pat. No. 5,542,528        U.S. Pat. No. 5,839,573        U.S. Pat. No. 5,957,335        U.S. Pat. No. 6,435,341 B1        U.S. Pat. No. 6,513,650 B2        U.S. Pat. No. 6,540,070 B1        U.S. Pat. No. 6,854,595 B2        U.S. Pat. No. 6,959,839 B2        U.S. Pat. No. 7,503,453 B2        U.S. Pat. No. 2007/0074979 A1        US 2007/0090000 A1        US 2008/0067172 A1        US 2008/0073307 A1        US 2008/0093381 A1        US 2008/0116221 A1        WO 2006/050538 A1        WO 2008/014444 A2        
Notwithstanding the identified prior art, there remains a need for an improved dispensing cap for beverage containers.